In a commonly used rectifier device, conversion between an alternating current and a direct current is generally implemented by using a bridge rectifier formed by four Schottky diodes. However, while requirements on power efficiency and limitation on external space are increasing, the Schottky diode is gradually replaced by an N-type metal-oxide-semiconductor (MOS) transistor, and is disposed in a chip to occupy less space.
In the prior art, a switch controlling a MOS transistor includes a comparator module which includes three comparators that separately compare voltages of any two of a first alternating current input end, a second alternating current input end, and a direct current output end of a rectifier circuit, so as to control switches of four MOS transistors. However, because only one MOS transistor is disposed between the first alternating current input end and the direct current output end, and only one MOS transistor is disposed between the second alternating current input end and the direct current output end, that is, a difference between a voltage value of the direct current output end and a voltage value of the first alternating current input end, and a difference between the voltage value of the direct current output end and a voltage value of the second alternating current input end are only a voltage drop of one MOS transistor, their voltage values are close, which imposes a relatively high requirement on precision of the comparators. Moreover, in a case in which dysfunction occurs in a comparator, misjudgment is easily caused, which affects a normal function of the switch controlling the MOS transistor, and current leakage from the direct current output end to the first alternating current input end and the second alternating current input end is also easily caused, thereby ultimately causing poor chip consistency, and affecting the yield of mass production of chips.